We collected an outstanding data set from a crystals of the dual specificity phosphatase VHR complexed with vanadate. The data extended to at least 1.6 , and had an Rsym of 3.5% to 1.8 . This structure recently has been solved and provides insights into the transition state of phosphate hydrolysis. Several data sets were also collected from the catalytic domain of the LAR receptor tyrosine phosphatase. Data collected from frozen crystals of an anti-DNA Fab fragment are now being used to refine the structure of this antibody.